OS crossword puzzle

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Across
  1. 3. The command interpreter for the kernel
  2. 6. A system software between the user and the hardware
  3. 7. Small area of main memory
  4. 8. Provide interface between a process and the operating system
  5. 9. Simultaneous use of multiple processors to solve a problem
Down
  1. 1. The rapid switching of cpu between multiple processes in memory
  2. 2. The core of the operating system
  3. 4. A program in execution
  4. 5. A collection of related information defined by its creator
  5. 8. A buffer that holds output for a device that cannot accept interleaved data streams